Enhancing the tonal characteristics of digital images

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EP 1 377 029 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	30.03.2005 Bulletin 2005/13

(43)	Date of publication A2:
	02.01.2004 Bulletin 2004/01

(21)	Application number: 03076821.2

(22)	Date of filing: 12.06.2003

(51)	International Patent Classification (IPC)⁷: H04N 1/407

(84)	Designated Contracting States:
	AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR
	Designated Extension States:
	AL LT LV MK

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Priority:

24.06.2002 US 178260

(71)	Applicant: EASTMAN KODAK COMPANY
	Rochester, New York 14650 (US)

(72)	Inventor:
	Gindele, Edward Brooks, c/o Eastman Kodak Company Rochester, New York 14650-2201 (US)

(74)	Representative: Weber, Etienne Nicolas et al
	Kodak Industrie, Département Brevets, CRT, Zone Industrielle 71102 Chalon sur Saône Cedex 71102 Chalon sur Saône Cedex (FR)

(54)	Enhancing the tonal characteristics of digital images

(57) A method of producing a tone scale function which can operate on a source digital image to improve tonal characteristics, includes generating the tone scale function having a highlight tone scale segment and a shadow tone scale segment defined relative to a reference point on the tone scale function, and that is adapted to operate on the source digital image to improve its tonal characteristics by: using a first function with a monotonically decreasing slope characteristic to produce the highlight tone scale segment that includes points that are equal to or greater than the reference point; and using a second function with a monotonically increasing slope characteristic to produce the shadow tone scale segment that includes points that are equal to or less than the reference point.

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